The architecture supporting Policy and Charging Control (PCC) functionality is illustrated in FIG. 1 and disclosed in 3GPP TS 23.203 V13.0.1 that specifies the PCC functionality for Evolved 3GPP Packet Switched domain, including both 3GPP accesses (GERAN/UTRAN/E-UTRAN) and Non-3GPP accesses. For the purpose of the present invention, the PCC architecture includes a Policy and Charging Rules Function (PCRF), a Policy and Charging Enforcement Function (PCEF), a Traffic Detection Function (TDF) and, optionally, a Bearer Binding and Event Reporting Function (BBERF) and a Subscription Profile Repository (SPR).
The PCRF is a functional element that encompasses policy control decision and flow based charging control functionalities. The PCRF provides network control regarding the service data flow detection, gating, Quality of Service (QoS) and flow based charging (except credit management) towards the PCEF. The PCRF may receive session and media related information from an application function (AF) and may notify the AF of traffic plane events.
The PCRF provides PCC rules to the PCEF via a Gx reference point. The PCRF informs the PCEF, by means of the PCC rules, on the treatment of each service data flow that is under PCC control, in accordance with PCRF policy decisions.
The PCEF encompasses service data flow detection based on filters definitions included in the PCC rules, as well as online and offline charging interactions (not described here) and policy enforcement. Since the PCEF is the system element handling the bearers, this is where the QoS is being enforced for the bearer according to the QoS information received from the PCRF. The PCEF functional entity is located at a Gateway, such as e.g. a Gateway GPRS Support Node (GGSN) in the GPRS case, a Packet Data Network Gateway (PGW) in the EPS case, and a Packet Data Gateway (PDG) in the WLAN case.
The SPR is in charge of providing subscription data for a user to the PCRF via a Sp reference point. However, a User Data Repository (UDR), as disclosed in 3GPP TS 23.335 v12.0.0, may replace the SPR for provision of subscription data to the PCRF via a Ud reference point.
This PCC architecture may also include a Bearer Binding and Event Reporting Function (BBERF) which, for the purpose of the present invention, behaves in a similar manner and for a similar purpose as the PCEF, but for receiving and handling QoS rules, instead of PCC rules, via a Gxx reference point.
The TDF is a functional entity that performs application detection and reporting of detected application, and its service data flow description, to the PCRF via a Sd reference point. The TDF can act in solicited mode, i.e. upon request from the PCRF, or unsolicited mode, i.e. without any request from the PCRF. In order to perform the application detection, the TDF receives Application Detection and Control (ADC) rules from the PCRF via the Sd reference point, in a similar manner and for a similar purpose as the PCEF receives the PCC rules.
3GPP TS 29.212 V13.0.0 specifies the operations on PCC rules, ADC rules and QoS rules, as well as the particular parameters that a PCC rule, an ADC rule and a QoS rule may comprise. The PCC rules, ADC rules and QoS rules may be dynamic rules provisioned by the PCRF, or static rules respectively predefined at the PCEF, TDF and BBERF. The operations available for dynamic rules are: installation, modification and removal; whereas the operations available for static rules are: activation and deactivation.
A PCC rule and a QoS rule include a service data flow filter used to identify a service data flow, and one or more service data flow filters are used to select the traffic for which the PCC rule and the QoS rule applies. An ADC rule includes a TDF application identifier used to reference the corresponding application, for which the ADC rule applies. The same application identifier value can occur in more than one ADC rule and, if so, the PCRF ensures that there is at most one ADC rule active per application identifier value at any time.
The PCEF may include the TDF functionality. Where this is the case, a PCC rule may be complemented to include a corresponding ADC rule. In particular, the PCEF including the TDF receives PCC rules that include service data flow filters and application identifier.
For the sake of simplicity, and given the similar behaviour for the purpose of the present specification, the PCEF, BBERF and/or TDF are hereinafter indistinctly referred to as ‘PCEF/TDF’ unless otherwise specified. Likewise, PCC rules for the PCEF, QoS rules for the BBERF and ADC rules for the TDF are hereinafter indistinctly referred to as ‘control rules’ unless otherwise specified, whereas service data flow filter for a PCC rule or a QoS rule, and application identifier for an ADC rule, may respectively be referred to as ‘service’ and ‘application’ and are hereinafter indistinctly referred to as ‘service’ unless otherwise specified. Likewise, parameters of a PCC rule, an ADC rule and a QoS rule are hereinafter referred to as control rule parameters, unless otherwise specified.
A control rule with a number of control rule parameters can be installed, modified or removed by the PCRF. When a new control rule is installed by the PCRF, all the control rule parameters in the new control rule are enabled by the PCEF/TDF to enforce the new control rule. When an existing control, rule is removed by the PCRF, all the control rule parameters in the existing control rule are disabled or removed by the PCEF/TDF. When an existing control rule is to be modified by the PCRF, a modified control rule with one or more control rule parameters is submitted from the PCRF; the PCEF updates the existing control rule with the one or more control rule parameters in the modified control rule. To this end, the one or more control rule parameters in the modified control rule are enabled and overwrite the corresponding control rule parameters previously enabled in the existing control rule, and other control rule parameters previously enabled in the existing control rule and not included in the modified control rule remain enabled in the existing control rule.
At present, the inactivation or removal of a particular control rule parameter, or rather its parameter value, for a given control rule is possible by removing the given control rule and installing it again without the particular control rule parameter.
This limitation is even more severe where a particular control rule parameter is shared by more than one control rule and there is a need to remove the particular control rule parameter for a given control rule whilst maintaining this particular control rule parameter for other control rules. The only possibility nowadays is the removal of the given control rule followed by the installation again of the given control rule without the particular control rule parameter.
In this respect, similar limitations exist for the PCC rules over the Gx reference point, the ADC rules over the Sd reference point and the QoS rule over the Gxx reference point. For example, the parameters Sharing-Key-UL and Sharing-Key-DL are used to indicate which rules should share resources (GBR is calculated as the maximum GBR among them); and it is only possible to remove previously provided values by applying a fake value (a value that cannot be shared with other rules). Also for example, it is not possible nowadays to stop applying a maximum bandwidth to a PCC/QoS rule; it is only possible to provide a very high value that is never reached. A value of the bandwidth set to zero can be interpreted as gating.
That is, at present, the inactivation or removal of a particular control rule parameter associated with a given control rule, whilst maintaining this same particular control rule parameter for other control rules, is only possible by removing the given control rule and installing again the given control rule without including the particular control rule parameter.
However, removal of e.g. PCC rules in the PCEF may have signalling impacts in the network. If the PCC rule was bound to a dedicated bearer, the PCEF has to initiate the update/termination of the corresponding bearer. This procedure is time and resource consuming. Besides, the PCRF would have to install the new PCC Rule without such particular control rule parameter, and this would also require the establishment/update of the related dedicated bearer.